In various vehicle and non-vehicle platforms, a power source such as an engine may provide power to a transmission. An operator, an automated system, or another mechanism may select a particular gear ratio within the transmission, in order to convert the power from the power source to an appropriate torque or speed for a particular operation of the platform. For example, a shift fork or other gear engagement device may be used to engage a particular gear, which may provide a particular gear ratio for transfer of power through the transmission.
In certain embodiments, various gears for various gear ratios may be located along a single shaft within a transmission. This may be useful, for example, in order to minimize the space required for a given transmission with a particular set of gears. In this and other configurations, it may sometimes be possible for an operator (or other mechanism) to accidentally engage (or try to engage) more than one gear at a time. Because this may increase the potential for wear or other damage, or other undesirable effects, it may be useful to provide a mechanism that prevents selection (or attempted selection) of one gear while another gear is still engaged.